Occurrence of Sclerotinia Rot in Solanaceous Crops Caused by Sclerotinia spp

Solanaceous crops grown in greenhouses and fields in Korea were surveyed from 1994 to 2000. Sclerotinia rot most severely occurred up to 60% in potato. Incidence of the disease was as high as 20% at its maximum in tomato and 5% in eggplant, but as low as less than 1% in red pepper. Symptoms of Sclerotinia rot commonly developed on stems of the solanaceous crops but rarely on fruits of eggplant and tomato. A total of 169 isolates of Sclerotinia species was obtained from the diseased solanaceous crops. Out of the isolates, 165 isolates were identified as S. sclerotiorum, and the others as S. minor based on their morphological and cultural characteristics. S. sclerotiorum was isolated from all the solanaceous crops, while S. minor was only isolated from tomato. Eight isolates of S. sclerotiorum and two isolates of S. minor were tested for their pathogenicity to the solanaceous crops by artificial inoculation. All the isolates of the two Sclerotinia spp. induced rot symptoms on stems of the solanaceous crops tested, which were similar to those observed in the fields. The pathogenicity tests revealed that there was no significant difference in the susceptibility of the solanaceous crops to the isolates of S. sclerotiorum. However, in case of S. minor, the potato cultivar Sumi was relatively less susceptible to the pathogen.

Occurrence of Sclerotinia Rot on Composite Vegetable Crops and the Causal Sclerotinia spp

Composite vegetable crops grown in greenhouses and open fields in Korea were surveyed from 1995 to 1999. Occurrence of Sclerotinia rot was observed in 123 of 277 lettuce fields, in 11 of 18 head lettuce fields, in 12 of 14 endive fields, and in 4 of 38 garland chrysanthemum fields surveyed during the growing seasons. The disease most severely occurred up to 80% on lettuce. Incidence of the disease was as high as 20% at its maximum on endive and garland chrysanthemum but relatively low on head lettuce. Symptoms of the disease developed on leaves of all the composites, crowns of lettuce and head lettuce, and stems of garland chrysanthemum. Out of 240 isolates of Sclerotinia species obtained from the diseased composites, 169 isolates were identified as Sclerotinia sclerotiorum, and the others as S. minor based on their morphological and cultural characteristics. S. sclerotiorum was isolated from all the composites, and S. minor only from lettuce and endive. Eight isolates of S. sclerotiorum and four isolates of S. minor were tested for their pathogenicity to the composites by artificial inoculation. All the isolates of the two Sclerotinia spp. induced rot symptoms on the plants of the composites by artificial inoculation, which were similar to those observed in the fields. The pathogenicity tests revealed that there is no significant difference in virulence of the isolates to the composites and in susceptibility of the composites to the isolates.